A clever idea, however his data source is irrevocably corrupted by the auto exposure and auto white balance of his webcam. The result is, sadly, more influenced by the algorithms in his camera than the sky itself.

Notice how there's some outrageous and short-lived tones during sunrise and sunset -- that's the white balance jumping around (Possibly an automatic saturation gain too?)

Then notice how the brightness doesn't peak and fall during the day, instead jumping quickly from darkness to "full" brightness with frequent dramatic shifts far greater than reality would allow. That's because the moving cloud cover is triggering the auto exposure to jump around incessantly.

The ideal fix would be to replace the webcam with a digital camera capable of tethered shooting and fully manual operation. You'd fix the shutter, aperture and ISO values to a level that minimizes clipping, set the white balance to daylight, and point the camera in a direction least likely to be in the sun's path (in the southern hemisphere, that's south).

In order to capture the dynamic range fully, you could allow the camera to automatically choose the shutter speed, then compensate in the algorithm by reading the shutter speed from the EXIF data.

That said, full points for the idea, and for a great web app to visualize the data!

Some webcams have manual settings, I know mine does. Just enabling those should get you 90% of the way of a tethered digital camera, "all that remains" is getting sufficient dynamic range and fixing the curves/compensating for human perception.

Many cheap/consumer devices let you disable some automatic adjustment, but rarely do they let you disable everything. For example, I've seen webcams that can fix the white balance but have automatic saturation adjustment that can't be turned off.

The cheap option that comes to mind would be an old and/or second hand Canon PowerShot capable of running CHDK firmware. Ask friends and family; you'd probably be able to score one free from a dusty cupboard draw.

And it looks like, more than the auto-white balance thing, he's getting washed-out skies from overexposure. This is a very common problem in photography- ever take a photo somewhere with a blue sky dotted with clouds but in the photo the sky comes out solid white or gray? Go back and look at some of your old photos, you will notice it.

There is no easy solution without sacrificing exposure of the lower half (what is usually the subject) however in this case the subject IS the sky, so select a camera that has manual exposure, set it a little lower and you'll be all right.

I always wanted to make a wall-sized version of this with really bright LEDs-- kind of like a light therapy box, but programmed with the full progression of color and brightness of various locations and seasons around the world - summer in NYC, Paris in the springtime, New England in the winter, LA on a non-smoggy day, etc., with options for real-time data feeds, too.

So you could feel like you were in the best location in the world on the best day of the year. Or just synchronize your work/sleep schedule with some other timezone.

If the size of each block was reduced to a few pixels square you could fit an entire year in a single image (4 pixels * 12 * 24 = 1152 wide, 365 * 4 = 1460 high) - which might be nice way of visualizing what the weather is like in a location.

When I used to work in building design, I used to create lots of charts of various climate data for projects in new regions where I didn't know much about the climate (and also for eye candy in presentations). One of those charts was very similar to what you suggested. Basically a 2D array of coloured squares, with hour of the day along one axis and month of the year along the other. Then each square would be coloured according to the average solar radiation falling at that time of day in that month (using a blue-green-red type scale usually, but you can do grey scale or anything else you can think of). It was a useful way of visualising lots of stuff - variation in day length, strength of the sun, summer/winter variations, etc.

You can plot other variables like this too - temperature, humidity, ...